function model = rs_train(feat_train, score_train, train_method )

down_rate = 0.15;

dim = size(feat_train ,2);

down_n = floor( dim * down_rate );

if down_n == 0, down_n = 1, end

ord = randperm( dim );
ord = ord( 1:down_n );

model.sel_id = ord;
model.mod = train_method( feat_train( :, ord) , score_train );